1. Field of Invention
The present invention relates to soil remediation and more particularly to an integrated soil probe and method for facilitating soil remediation.
2. Background Information
Soil treatment for removing contaminants from surface soil has been of growing interest in recent years. Many methods are known for removing soil contaminants including excavating contaminated soil followed by incineration, in situ biological treatment of the soil, chemical treatment of the soil, etc. As used in the context of the present invention, soil is to be inclusive of landfills and other contaminated media.
Heating of the soil is known to facilitate soil remediation by: increasing the rate of chemical reactions for chemical treatment methods, increasing biological activities within biological treatment methods, vaporizing contaminates in vaporization processes, increasing the oxidation efficiency of oxidation treatments, and or simply facilitating thermal decomposition techniques. Examples of such heating methods include providing solar greenhouse covers over excavated contaminated soil, direct fired heating of excavated soil, and in situ warming of the soil by electricity.
Greenhouse covers warm the soil with limited temperature affects. The limited temperature limits the speed of soil remediation. Direct fired techniques require costly soil removal and transfer of the contaminated soil to and through a reactor furnace.
The techniques for heating soil electrically present another set of problems. Energy conversion efficiency is poor in producing electricity of 60 Hz or RF frequencies. High costs are associated with systems for handling the high voltage electricity and distributing it to desired electrodes in the ground. In addition, the required high voltages, i.e. 10 kV, present hazards when presented to ground level electrodes. Finally, the electrical techniques warm the ground non-uniformly, leaving hot spots within the ground that result from dielectric/resistivity variations with the geological structure of the ground.
Another technique for warming soil employs a thermal probe. The thermal probe is inserted into soil and heated for radiating heat to the soil. In heating the probe, hot water (or another heated liquid) is circulated through the probe. The thermal probe provides a safe and energy effective warming method, but has limited thermal conductivity to the surrounding soil. Because of the probe's limited thermal conductivity to the surrounding soil, steep temperature gradients exist within the soil surrounding the thermal probe resulting in non-uniformity of soil temperature.